Granular material such as grain and like agricultural products are commonly transported in trailers with hoppered compartments. The granular material is discharged through an opening in the bottom center of the trailer. To receive this discharged material a conveyor intake is located under the discharge opening. In permanent conveyor installations the trailer is commonly driven over a receiving pit and the material is directed to the conveyor intake.
In many industries however, such as agriculture, portable conveyors are used which are moved from location to location. These portable conveyors typically include a transfer conveyor with a conveyor intake located under the trailer discharge opening, and a conveyor discharge oriented to discharge into the intake of a main conveyor. One such common transfer conveyor is a swing auger pivotally attached to the main conveyor intake, such as disclosed in U.S. Pat. No. 8,662,285 to Jesse. The conveyor intake is provided by a receiving container with sides sloping to direct received material into one or more generally horizontal augers, which carry the material to an inclined auger which in turn carries the material to the main auger.
It is also known to configure the transfer conveyor intake such that the trailer drives over the intake to locate the trailer discharge over the intake. U.S. Pat. No. 5,964,566 to Stewart et al. discloses a drive-over transfer conveyor where the conveying mechanism is provided by a chain with paddles which provides a low profile to facilitate driving over the intake. U.S. Pat. No. 4,813,839 to Compton discloses a drive-over transfer conveyor where the conveying mechanism is provided by a belt which also provides a low profile.
U.S. Pat. No. 7,090,066 to Kirsch discloses a drive-over transfer conveyor where the conveying mechanism inside the receiving container is provided by a pair of horizontal augers. The ramps of Kirsch are configured to fold up to provide a sufficient ramp length to allow a trailer to roll over the top of the receiving container which is higher than that of Stewart et al.
Since the capacity of an auger is related to its diameter, the augers in such transfer conveyors must have a sufficiently large diameter to provide the desired capacity. Typically there are two to three horizontal augers, each with a diameter of 6 inches or more.
Some products such as oilseeds and fertilizer are problematic for conveying with a belt conveyor. Oilseeds such as canola are very small and slippery and leak into various areas of the conveyor and build up a gummy accumulation on rollers and other parts. Some fertilizers react with rubber belting reducing belt life.